Romney, the presumptive Republican presidential nominee, told radio host Laura Ingraham on Wednesday that people should be fired who put "their personal play time" ahead of the nation's interests. He suggested a lack of leadership led to scandal, which involved at least 20 women, but said he has confidence in Secret Service Director Mark Sullivan.

"I'd clean house," Romney told Ingraham when asked how he would address the situation. "The right thing to do is to remove people who have violated the public trust and have put their play time and their personal interests ahead of the interests of the nation."

In an earlier radio interview, Romney said he shared Obama's confidence in the Secret Service chief.

"We are a nation, after all, under law and the president has confidence in the head of the Secret Service, as do I," Romney said. "I believe that the right corrective action will be taken there and obviously everyone is very, very disappointed in these stories, very uncharacteristic of the service."

Romney, unlike some GOP critics on Capitol Hill, has been receiving around the clock Secret Service protection for more than two months.

The situation has become an election-year embarrassment for Obama, who has said he'd be angry if the allegations are true.

Sullivan, facing questions on Capitol Hill about whether the escapades could have jeopardized the president's security, said he had referred the matter to an independent government investigator.

He said the 11 Secret Service agents and 10 military personnel under investigation were telling different stories about who the women were. Sullivan has dispatched more investigators to Colombia to interview the women, said Rep. Peter King, R-N.Y., chairman of the House Homeland Security Committee.